"""
B0.3.3 — export the API contract.

Writes openapi.json at the repository root. It is committed, and CI fails when
the exported document differs from the committed one, so a change to a request
or response shape has to be admitted in a diff rather than discovered by the
frontend at runtime.

    APP_ENV=rework_test python scripts/export_openapi.py          # write
    APP_ENV=rework_test python scripts/export_openapi.py --check  # verify

The contract is exported now, at 31% `response_model` coverage, rather than
after B0.3.1/B0.3.2 fill the remaining 166. An incomplete contract that cannot
silently change is worth considerably more than a complete one that arrives in
three weeks, and every endpoint that gains a `response_model` shows up as a diff
here — which makes progress visible instead of merely claimed.
"""

import json
import os
import sys
from pathlib import Path

os.environ.setdefault("APP_ENV", "rework_test")
os.environ.setdefault("PYTHONIOENCODING", "utf-8")

sys.path.insert(0, str(Path(__file__).parent.parent))

OUTPUT = Path(__file__).parent.parent / "openapi.json"


def build() -> str:
    from app.main import app

    schema = app.openapi()
    # sort_keys so the file is diffable: FastAPI does not guarantee key order,
    # and an unordered dump would churn on every export.
    return json.dumps(schema, indent=2, sort_keys=True, ensure_ascii=False) + "\n"


def main() -> int:
    generated = build()
    check = "--check" in sys.argv

    if check:
        if not OUTPUT.exists():
            print("openapi.json is missing. Run scripts/export_openapi.py", file=sys.stderr)
            return 1
        committed = OUTPUT.read_text(encoding="utf-8")
        if committed != generated:
            print(
                "openapi.json is stale — the API has changed since it was exported.\n"
                "Regenerate and commit the diff:\n"
                "    APP_ENV=rework_test python scripts/export_openapi.py",
                file=sys.stderr,
            )
            return 1
        print("openapi.json is current")
        return 0

    OUTPUT.write_text(generated, encoding="utf-8")
    schema = json.loads(generated)
    print(f"wrote {OUTPUT.name}")
    print(f"  paths   {len(schema.get('paths', {}))}")
    print(f"  schemas {len(schema.get('components', {}).get('schemas', {}))}")
    return 0


if __name__ == "__main__":
    raise SystemExit(main())